The present invention relates to the technical field of radiation imaging (radiation image taking/recording), in particular, to an apparatus and a method for radiation imaging by which the right and left breasts of a subject can be taken with proper register attained between their positions in mammography.
In breast cancer screening, the success rate of early detection that is achieved through physical examination by inspection and palpation only is improved if it is combined with mammography by a radiation image taking apparatus solely intended for breasts (which is hereinafter referred to as a breast imaging apparatus); hence, breast cancer screening that is currently practiced involves the use of a breast imaging apparatus in addition to (or in place of) inspection and palpation.
The breast imaging apparatus comprises an imaging table enclosing a radiation image recording medium (which is hereinafter referred to as an imaging medium); to operate it, the breast is placed on the imaging table, compressed with a press plate, irradiated with a radiation from the press plate side; the radiation transmitted through the breast is received by the imaging medium and its radiation image is taken on the imaging medium.
Diagnosis on radiation images can be performed with greater ease if the radiograph of interest is interpreted in comparison with a reference image. For this reason, mammography is commonly performed with the images of the right and left breasts of a subject being placed side by side for interpretation and diagnosis.
For proper diagnosis, it is preferred that the right and left breasts are imaged symmetrically. To this end, the (imaging) radiologist may adjust the positions of the breasts and the like (perform positioning) while they are compressed with a press plate; however, the current practice of breast radiography largely depends on the skill of the radiologist for proper adjustment of breast position and the like.
JP 2005-261846 A, JP 2006-43187 A, and JP 2006-55419 A show techniques in which, for the purpose of performing diagnosis with the images of the right and left breasts placed side by side, the image data obtained by imaging (taking/recording) the right and left breasts are processed to extract the breast images, which are brought into register and synthesized into a single image.